To provide a warm keeping chamber accommodating a heat reservoir, whose inside can be kept at a high temp. and overall outside dimensions be made small.

Rack columns 10 (-13) for supporting trays 5 to accommodate the food at stages are installed upright at the four inside corners of a warm keeping chamber. Panel-form heat emitting units 4 are arranged in the inter-columnar spaces 8L, 8B, 8R between the rack columns 10 (-13) so as to hinder the body 1 of the chamber from enlarging. Each heat emitting unit 4 is configured so that a heater 31 and a heat reservoir 32 are arranged inside a hollow panel 30 made from a metal plate. The units 4 are arranged opposingly through an aeration gap E with respect to the internal walls of the chamber, and the intra-chamber air is heated by the heat emitted from the internal and external panel surfaces. Thereby the heat emitting quantity of the units 4 is increased and the intra-chamber temp. is kept high.